The human vertebral column (also known as the backbone or spine) houses the spinal cord in its spinal canal. The vertebral column is made up of a plurality of vertebrae. A typical vertebra includes two primary parts, including an anterior portion that includes the vertebral body, and a posterior portion that encloses the foramen. Each vertebral body defines superior and inferior vertebral endplates that, such that adjacent vertebrae define an intervertebral space that includes disc material between the respective endplates.
Historically, spinal abnormalities have indicated complete removal of a disc from the intervertebral space followed by fusion the adjacent vertebrae together. This “spinal fusion” procedure, which is still in use today, is a widely accepted surgical treatment for symptomatic lumbar and cervical degenerative disc disease. Early fusion procedures used an implant made of bone from a patient's hip or a cadaver bone as a spacer in the intervertebral space so as to properly position the adjacent vertebrae until the vertebrae were fused together. More modern procedures use implants made from a material having a relatively low modulus of elasticity to encourage bone growth. For instance, the implant can contain some of the patient's own bone, e.g., within apertures of the implant. Conventional implants can be made from desired material, including radiolucent materials such as polyetheretherketone (PEEK), ultra-high molecular weight polyethylenes (UHMWPE) or polysulfones (PSU). It can be desirable for the material to have a modulus of elasticity between 3 and 5 GPa.
Conventional intervertebral implant designs have attempted to achieve implant fixation in the intervertebral space.